Polymerization with multifunctional iniators prepared from vinylsilanes or vinylphosphines and organomonolithium compounds

ABSTRACT

Multifunctional polymerization initiators are prepared by reacting an organomonolithium compound with a polyvinylsilane compound or polyvinylphosphine compound.

United States Patent Ralph C. Farrar Bartlesville, Okla.

Jan. 30, 1969 Nov. 30, 1971 Phillips Petroleum Company Inventor Appl.No. Filed Patented Assignee POLYMERIZATION WITH MULTIFUNCTIONAL INIATORSPREPARED FROM VINYLSILANES OR [50] Field of Search 260/942 M, 83.7, 665;252/431, 431 P [56] References Cited UNITED STATES PATENTS 3,135,7166/1964 Uraneck et a1. 260/942 3,383,377 5/1968 Uraneck et al. 260/94.7

Primary Examiner-James A. Seidleck AI!orney-Young and Quigg ABSTRACT:Multifunctional polymerization initiators are prepared by reacting anorganomonolithium compound with a polyvinylsilane compound orpolyvinylphosphine compound.

nylphosphine compounds. In another aspect, this invention relates to animproved process for polymerizing'conjugated dienes,monovinyl-substituted aromatic compounds, and mixtures thereof.

It has now been surprisingly discovered that a versatile multifunctionalpolymerization initiator can be formed by reacting an organomonolithiumcompound with a polyvinylsilane compound or a polyvinylphosphinecompound.

It is an object of this invention to provide a new lithiumbasedinitiator. It is an object of this invention to provide "an improvedprocess for the polymerization of polymerizable conjugated dienes,vinyl-substituted aromatic compounds and mixtures thereof. It is anobject of this invention to provide an improved block copolymerpossessing a high 'Mooney viscosity value and exhibiting high greentensile strength when prepared from conjugated dienes andmonovinyl-substituted aromatic compounds and employing themultifunctional polymerization initiator of this invention.

Other objects, features, and advantages of my invention will be apparentto those skilled in the art from the following discussion anddisclosure.

The multifunctional polymerization initiators" of my invention areprepared by reacting an organomonolithium compound with apolyvinylphosphine compound or polyvinylsilane compound. The reaction isconducted in the presence of an inert diluent such as a hydrocarbon orpolar compound, or mixtures thereof.

Exemplary of some of these hydrocarbon diluents that can be employed areparaffins, cycloparaflins, and aromatics containing from four to 12carbon atoms. Exemplary of some polar compounds suitable for employmentaccording to my invention are ethers, thioethers, tertiary amines andthe like. Exemplary hydrocarbons are propane, isobutane, n-pentane,isooctane, cyclohexane, benzene, toluene, and the like.

While very etficient initiators can be prepared by employing only thoseaforementioned hydrocarbon or polar diluents; it is preferred to reactthe organomonolithium compound and the polyvinylsilane orpolyvinylphosphine compound in the presence of a solubilizing monomer,i.e., a polymerizable conjugated diene or monovinyl-substituted aromaticcompound, or mixtures thereof as an additional initiator component.These polymerizable compounds exert a solubilizing action on thereaction product of the organomonolithium compound and thepolyvinylsilane or polyvinylphosphine compound and thus enhance theefficiency of the initiator produced. These polymerizable compounds willbe subsequently referred to as solubilizing monomers.

Generally conjugated dienes containing from four to l2 and preferablyfour to six carbon atoms per molecule, such as 1,3- butadiene, isoprene,piperylene, 2,3-dimethyl-l,3-butadiene, and the like, andmonovinyl-substituted aromatic compounds containing eight to 20preferably eight to 12 carbon atoms per molecule, such as styrene,alkylated styrene, l-vinylnaphthalene and the like, can be so employedas solubilizing monomers. Mixtures of these solubilizing compounds canalso be used. I

The multifunctional initiators produced according to this invention arebranched with the branching being terminated v with at least two lithiumsubstituents which serve as'reaction sites for polymerization atmultiple positions.

Branched polymers are consequently made when prepared with theseinitiators. The polymers exhibit little if any'cold flow tendencies andare substantially gel free. Relatively high green tensile strength isexhibited in the case of the aforementioned block copolymers. v

The organomonolithium compounds employed for the initiator preparationaccording to this invention are represented by the formula RLi, whereinR is an aliphatic, cycloaliphatic,

or aromatic radical, or combinations thereof, preferably containing fromtwo to 20 carbon-atoms. Exemplary of these organomonolithium compoundsare ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium,sec-butyllithium, tertoctyllithium, n-decyllithium, -n-eicosyllithium,phenyllithium, Z-naphtyllithium, 4-butylphenyllithium, 4-tolyllithium,4- phenylbutyllithium, cyclohexyllithium,3,5-di-n-heptylcyclohexyllithium, 4-cyclopentylbutyllithium, and thelike. The 'alkyllithium compounds are preferred for employment accordingto this invention, especially those wherein the alkyl group containsfrom three to 10 carbon atoms.

polyvinylsilane compounds employed according to this invention can berepresented by the formula R" Si, wherein R" is a hydrocarbon radicalselected from vinyl, saturated aliphatic, saturated cycloaliphatic, andaromatic radicals, and combinations thereof with at least two of saidradicals being vinyl and wherein each of the remaining radicalspreferably contain from one to 12 carbon atoms. Exemplary ofpolyvinylsilanecompounds that can be employed according to thisinvention are tetravinylsilane, methyltrivinylsilane,diethyldivinylsilane, n-hexyltrivinyls'ilane, di-n-dodecyldivinylsilane,cyclohexyltrivinylsilane, diphenyldivinylsilane, phenyltrivinylsilane,methylphenyldivinylsilane, benzyltrivinylsilane,cyclohexylphenyldivinylsilane, dodecylcyclopentyldivinylr silane,2-butyltrivinylsilane, (3-ethylcyclohexyl)(3-n-butylphenyl)divinylsilane, (4-cyclohexylphenyl)trivinylsilane,4-cyclohexyll -butyl)( 3-phenyll -hexyl )divinylsilane,

(3,5 ,6-triethylcyclohexyl )trivinylsilane,(2-methyl-3-phenylcyclopentyl)trivinylsilane, dimethyldivinylsilane,dicyclohexyldivinylsilane and the like.

Polyvinylphosphine compounds employed according to this invention can berepresented as R,P wherein R is a hydrocarbon radical selected fromvinyl, saturated aliphatic, saturated cycloaliphatic, and aromaticradicals, and combinations thereof, with at least two of said radicalsbeing vinyl and with the remaining radical, if any, preferablycontaining from one to 12 carbon-atoms.

Exemplary polyvinylphosphine compounds that can be employed according tothis invention are trivinylphosphine; methyl divinylphosphine; dodecyldivinylphosphine; phenyl divinylphosphine; cyclooctyl divinylphosphine;(S-phenyl-lhe'xyl)divinylphosphine;(4-phenylcyclohexyl)divinylphosphine;(3-cyclopentylphenyl)divinylphosphine; (2-ethylphenyl)divinylphosphine;(3-methylcyclohexyl)divinylphosphine;3-cyclohexyl-2-butyl)divinylphosphine;(3,5-di-n-propylphenyl)divinylphosphine; 3-octyl divinylphosphine; andthe like.

As hereinbefore stated, the preparation of the initiators of thisinvention is conducted in the presence of an inert diluent such ashydrocarbon or polar diluent. This reaction between the polyvinylsilaneor polyvinylphosphine compound and the organomonolithium compoundgenerally results in the formation of precipitate. The precipitate canbe solubilized as it is formed by conducting the reaction in thepresence of a minor amount of solubilizing monomer i.e.,monovinyl-substituted aromatic compound or conjugated diene, e.g'.styrene, butadiene, or isoprene. In another method of operation thepolyvinylsilane or polyvinylphosphine compound and the organomonolithiumcompound can be reacted first, then the solubilizing monomer added andthe reaction mixture agitated to facilitate solution of the precipitate.Regardless of the method of operation, however, multifunctionalinitiators are obtained.

The relative amounts of organomonolithium compound and polyvinlysilanecompound or polyvinylphosphine compound can be expressed in terms ofmoles of organomonolithium compound per mole of vinyl group in 1 mole ofthe polyvinylsilane or polyvinylphosphine compound. Generally in therange of 0.33 to 4 moles of organomonolithium compound per mole of vinylgroup present in one mole of polyvinylsilane or polyvinylphosphinecompound is employed.

The functionality of an initiator prepared according to the inventioncan be increased by increasing the number of vinyl groups in thepolyvinylsilane compound or polyvinylphosphine compound if the lithiumis held constant, or by increasing the ratio of moles of particularpolyvinylsilane compound or polyvinylphosphine compound to gram atoms oflithium in the system.

The temperature employed for preparing the initiators of this inventionis in the range of about 35 C. to l25 C., preferably 30 C. to 100 C. Thereaction time will generally depend upon the temperature employed andwould be in the range of about seconds to 48 hours with a preferred timeof from 1 to 24 hours. It is also to be understood that a longerreaction time would promote branching in the initiator but an excessivereaction period could lead to cross-linking, i.e., gel formation. It isthus evident that for a given mole ratio of reactants one can regulatetemperature and time in order to obtain a gel free branched initiator.

The quantity of solubilizing monomer, if employed, will vary dependingupon such variables as the polyvinyl compound and organomonolithiumcompound employed, the mole ratios of these compounds, and thetemperature and time of the reaction. Soluble initiators can be preparedwith as little as 2 gram millimoles of solubilizing monomer per grammillimole of organomonolithium compound. Larger quantities can be usedas desired to effect solubilization.

The polymers which can be prepared using the multifunctional initiatorsof this invention include homopolymers of conjugated dienes containingfrom about four to carbon atoms per molecule, copolymers of two or moreconjugated dienes, homopolymers of monovinyl-substituted aromaticcompounds containing eight to carbon atoms per molecule, copolymers oftwo or more monovinyl-substituted aromatic compounds, and copolymers ofconjugated dienes with monovinyl-substituted aromatic compotinds.

Exemplary monomers that can be employed with the multifunctionalinitiators of this invention are 1,3-butadiene; isoprene; piperylene;2,3-dimethyl-l,3-butadiene; 1,3-octadiene; 4,5-diethyl-l,3-octadiene;styrene; 3-methylstyrene; 3,5-diethylstyrene; 4-n-propylstyrene;2,4,6-trimethylstyr ene; 3-methyl-5-n-hexylstyrene;2,3,4,5-tetramethylstyrene; 4- dodecylstyrene; 4-cyclohexylstyrene;4-phenylstyrene; 4-ptolylstyrene; l-vinylnaphthalene;2-vinylnaphthalene; 4- methyl-l-vinylnaphthalene;3-ethyl-2-vinylnaphthalene; 4,5- dimethyl-l-vinylnaphthalene;4,5-diethyl-2-vinylnaphthalene; 6-isopropyl- 1 -vinylnaphthalene;2,4-diisopropyl- 1 -vinylnaphthalene;4-n-propyl-5-n-butyl-2-vinylnaphthalene, and the like.

This invention provides a method for obtaining rubbery block copolymersof conjugated dienes and monovinyl-substituted aromatic compounds thathave high green tensile strength. Multiple blocks of polymerizedmonovinyl-substituted aromatic compounds are essential for obtaining thehigh degree tensile strength desired. Resinous block copolymers can beprepared when a predominant amount of monovinyl-substituted aromaticcompound and a moderate amount of conjugated diene compound areemployed. High impact resins with a high degree of clarity and otherbeneficial properties can be prepared using the multifunctionalinitiators of this invention. When compounded with ingredients known inthe art the low molecular weight polymers produced according to thisinvention can be used as plasticizers, caulking compounds, sealants,potting compounds, coating compounds, and the like. The high molecularweight polymers have application as adhesive compositions, shoe sole,floor tile, tire tread, hose, belting, gaskets, and the like.

Polymerization conditions known in the art can be suitably employed whenusing the multifunctional polymerization initiators of this invention.Polymerization temperatures can vary over a broad range and aregenerally from about 70 to l50 C. It is preferred to operate at atemperature of at least 30 C. and above.

It is preferred that the polymerization be conducted in the presence ofa diluent such as benzene, toluene, xylene, cyclohexane,methylcyclohexane, n-butane, n-hexane, n-heptane, isooctane, mixtures ofthese, and the like. Generally, the diluent is selected fromhydrocarbons, i.e., paraffins, cycloparaflins, and aromatics containingfrom four to 10 carbon atoms per molecule.

The amount of initiator used in the polymerization process depends uponthe particular multifunctional polymerization initiator employed and thetype of polymer desired. An effective initiator level is normally in therange of about 0.2 to 100, preferably 1 to 50 gram milliequivalents oflithium per grams of monomer (mehm) charged.

The milliequivalents of lithium can be conveniently determined byalkalinity titration of a known volume of a reaction mixture containingthe multifunctional initiator. Said alkalinity titration employsstandardized acid, e.g., hydrochloric acid and an indicator such asphenolphthalein to determine the end point of the titration. Thealkaline normality thus obtained provides a value for themilliequivalents of lithium per milliliter of reaction mixturecontaining the multifunctional initiator. The alkalinity concentration(normality) thus determined is then employed for charging the knownquantity of equivalents of lithium in polymerization recipes employingthe multifunctional initiators of this invention.

When a polymerization is conducted in the presence of a multifunctionalinitiator of this invention, the unquenched polymerization mixture has abranched structure and the branches contain terminal lithium atoms.Treatment with various agents such as carbon dioxide, epoxy compounds,and the like, yield polymers with terminal functional groups on theseveral polymer branches that contained the terminal lithium atoms.Polymers of this type can be cured easily to form a tight network byreacting with various known polyfunctional reagents. As an example, alow molecular weight polymer of polybutadiene containing multiplecarboxy groups can be cured to a solid polymer with a polyfunctionalaziridinyl compound or a polyfunctional epoxy compound.

Illustrative of the foregoing discussion and not to be interpreted as alimitation on the materials herein employed, or on the scope of myinvention, the following examples are provided.

EXAMPLE I A multifunctional polymerization initiator was prepared byreacting sec-butyllithium with phenyltrivinylsilane. Another initiatorwas prepared from sec-butyllithium and tetravinyltin. The recipes wereas follows:

Toluene. ml. H0 H0 Phenyltrivinylsilane, mmoles l0 Tetravinyltin, mmolesl0 sec-Butyllithium, mmoles 20 20 l,3-Butadiene, ml. 8 8 Temperature, C.70 70 Time, minutes 75 70 Normality, based on lithium 0. l 50 0. H2

temperature was then adjusted as aforesaid to 70 C. The nor mality wasdetermined by titration of an aliquot of the reaction mixture with 0.1 Nl-iCl. Each of these initiators was then used for the randomcopolymerization of butadiene with styrene. Prior to the termination ofthe polymerization each reaction mixture was treated with stannicchloride to determine the degree of coupling that could be obtained. Therecipe was as follows:

1.3-Butndiene. parts by wt. Styrene. parts by wt.

Cyclohexane. parts by wt. 760 Tetrahydrofuran, parts by wt. 1.5Initiator. mehm variable Temperature. C. 70 Time. minutes variableStannic chloride. mhm variable Gram milliequivalents lithium per I00grams monomers Grain millimoles per 100 grams monomers in each run,cyclohexane was charged first followed by a nitrogen purge. Butadienewas added next then styrene followed by tetrahydrofuran, and initiator.The temperature was adjusted to 70 C. for the polymerization. At theconclusion of EXAMPLE ll Three multifunctional polymerization initiatorswere prepared by reacting sec-butyllithium with trivinylphosphine inthese runs. toluene was charged first followed by a nitrogen purge, thenbutadiene was added. Trivinylphosphine was added next followed bysec-butyllithium and the temperature adjusted to 70 C. for the desiredreaction time.

The multifunctional initiators that were produced above were thenemployed in polymerization runs according to the following recipe:

' Determined according to procedure of ASTM 1) 1646413. Not detected.

Runs I through 6 were made according to the invention and the pronouncedMooney jump accompanied by the formation of gel as a result of stannicchloride treatment shows that a branched polymer is obtained and saidbranched polymer was produced from the multifunctional initiatorprepared from the phenyltrivinylsilane. Runs 7-l 3 were made with thetetravinyltin initiator in contrast to the polyvinylsilane compound ofthis invention. There was little, if any, branching in these polymersevidenced by only a small increase in inherent viscosity and the lack ofgel as a result of treatment with stannic chloride. The lack ofbranching in these polymers indicate that the initiator prepared fromthe vinyltin compound did not have the functionality obtained when theinitiator was prepared from the polyvinylsilane compounds of thisinvention.

618. 3,278,508, col. 20, notes a and b.

each polymerization stannic chloride was added and after [0Polymerization Recipe minutes a 10 weight percent solution of anantioxidant, 2,2-

methylene-bis(4-methyl-6-tert butylphenol), in a mixture of Parts byWeight equal parts by volume of toluene and isopropyl alcohol. was addedin an amount sufficient to provide one part by weight of cyclohexane 760antioxidant per 100 parts by weight of the polymer. The Butadiene 7spolymer was coagulated in isopropyl alcohol and separated i' f f THF)and dried. One run was made with each initiator in which no 'z mvaria'ble stannic chloride was added. Results are shown in Table l.Dibulyllin dichloride (Bu,SnCl,) variable TABLE I Poly. Gel,

Li, time, SnCh, Conversion, Inherent per- ML-4 at Run No. mehm. min. mhmpercent viscosity cent 212 F.

I Initiator from phenyltrlvinylsilane Initiator from tetravinyltin 7 332 0 100 0.86 0 s 3 32 0. 16 100 0. 91 0 9 3 32 0. 3B 100 0. 99 0 10 332 0. 75 100 1. 05 0 11 2 a2 0 100 1.03 0 12 2 32 0.25 100 1.28 0 13 232 0. 50 100 1. 38 0 I Gram milliequivalents lithium per 100 rams ofmonomer.

in these polymerization runs, cyclohexane was first charged followed bya nitrogen purge. Butadiene was added next then styrene followed bytetrahydrofuran. The initiator was charged next and the temperature wasadjusted to 70 C. for

the polymerization reaction. The coupling agent (Bu snCl nylphosphineare multifunctional. polymerizable monomer with a multifunctionalpolymeriza- TABLE III Ll, Time, BurSnCi: Conv. Inherent Mooney Delta RunNo. mehm. min. mhm. percent viscosity ML-4 AML-4 Initiator from Run No.1

Initiator from Run No. 2

Initiator from Run No. 3

I mehm=gram milliequivalents lithium per 100 grams of monomers.

b mhrn= gram millimoies per 100 grams of monomers.

AML-4=difference in M00 and the experimental run.

EXAMPLE III Two multifunctional polymerization initiators were 25prepared by reacting sec-butyllithium with tetravinylsilane. The effectof varying the amounts of tetravinylsilane was determined. Recipes forpreparing initiators were as follows:

The procedure for preparing the initiators was the same as described inexample i.

Each of these initiators was used for the random 40 copolymerization ofbutadiene with styrene. The polymerization recipe was the same asemployed in example I. The temperature was 70 C. Prior to termination ofthe polymerization reaction each reaction mixture was treated withdibutyldichlorotin to detennine the degree of coupling that could beobtained. The procedure for recovering the polymer was the same as inexample I. One run was made with each initiator in which nodihutyldichlorotin was employed. Results are presented in table IV.

ney viscosity of the control run (no coupling agent added) tioninitiator under polymerization conditions including a polymerizationtemperature in the range of about to 150 C., said multifunctionalpolymerization initiator is employed in said process in an amountsufficient to provide from about 0.2 to I00 gram milliequivalents oflithium per 100 grams of said polymerizable monomer,

wherein said at least one polymerizable monomer is a conjugated diene offrom four to 10 carbon atoms per molecule, monovinyl-substitutedaromatic compound of from eight to 20 carbon atoms per molecule, ormixture thereof,

wherein said multifunctional polymerization initiator is that whichforms on reacting (l) an organolithium compound with (II) apolyvinylsilane compound or polyvinylphosphine compound, in the presenceof (iii) an inert hydrocarbon or polar diluent, and in the furtherpresence of (IV) an effective minor amount of a solubilizing monomersaid minor amount being sufficient to effect substantial solution ofsaid multifunctional polymerization initiator in said diluent,

wherein said (I) organomonolithium compound 'is RLi wherein R containsfrom two to 20 carbon atoms and is an aliphatic, cycloaliphatic,aromatic radical, or combination thereof,

said (ll) polyvinylsilane compound is R"Si wherein R" is a hydrocarbonradical and is vinyl, saturated aliphatic, saturated cycloaliphatic,aromatic radical, or combina- TABLE IV Poly Gel Initiator time, Bu:SnCh, Conversion Inherent per- MM from run Li, mehm. mhm. percentviscosity cent at 212 F.

2 27 3 0 99 2. 49 0 Not detected.

2 27 3 0. 100 3. b8 0 Do.

The above data demonstrate that by adjusting the initiator levels of theparticular initiator, products of the desired inherent viscosity can beproduced. The above initiators are multifunctional as evidenced by theincrease in Mooney viscosity and inherent viscosity as the couplingagent level was increased.

. As will be evident to those skilled in the art, various modificationsof this invention can be made or followed, in light of 70 the discussionand disclosure herein set forth without departing from the scope andspirit thereof.

lclaim:

l. A polymerization process for producing branched polymers whichcomprises polymerizing at least one 75 tion thereof, wherein at leasttwo said R"radicals are vinyl and each remaining R" radical containsfrom one to l2 carbon atoms;

said (II) polyvinylphosphine is R wherein R is a hydrocarbon radical andis vinyl, saturated aliphatic, saturated cycloaliphatic, aromatic. orcombination thereof. wherein at least two said R radicals are vinyl andthe remaining R radicals contain from one to 12 carbon atoms;

(lV) said solubilizing monomer is a polymerizable conjugated diene,polymerizable monovinyl-substituted aromatic compound, or mixturethereof,

wherein from about 0.33 to 4 moles of said RLi is employed per mole ofvinyl group present in each mole of said pdiyvinysilane compound orpolyvinylphosphine compound, and wherein said reacting is conducted forfrom about seconds to 48 hours at a reaction temperature of from about35 C. to 125 C.

2. The process of claim 1 wherein said polymerization temperature is atleast 30 C,,

said solubilizing conjugated diene monomer contains from four to 12carbon atoms per molecule, said solubilizing monovinyl-substitutedaromatic compound contains from eight to 20 carbon atoms per molecule,

said inert diluent is a paraffin, cycloparaflin, aromatic, or

polar compound,

wherein at least 2 gram millimoles of said solubilizing monomer areemployed per gram millimole of said RLi, and said reacting is conductedfor a time of from I to 24 hours at a temperature in the range of +30 C.to 100 C.,

and wherein said polymerization process is conducted in the presence ofa hydrocarbon diluent of from four to carbon atoms per molecule.

3. The process of claim 2 which further includes treating the unquenchedpolymerization mixture with carbon dioxide or an epoxy compound.

4. The process of claim 2 wherein said polymerization process is acopolymerization process. said branched polymer is a copolymer, said atleast one polymerizable monomer includes at least one conjugated dieneand one monovinyl-substituted aromatic compound.

5. The process of claim 4 wherein said polymerizable conjugated diene is1,3-butadiene, said polymerizable monovinylsubstituted aromatic compoundis styrene, and said multifunctional polymerization initiator isprovided in an amount of l to 50 gram milliequivalents of lithium perI00 grams of said polymerizable monomer charged.

6. The process according to claim 5 wherein said RLi is secbutyllithium,and said polyvinylsilane compound is employed and is tetravinylsilane orphenyltrivinylsilane, and wherein said solubilizing monomer isLB-butadiene.

7. The process according to claim 5 wherein said RLi is secbutyllithium,wherein is employed said polyvinylphosphine compound and istrivinylphosphine, and wherein said solubilizing monomer is1,3-butadiene.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 6Z4057 Dated November 30 1971 Inventor(s) Ralph C rrar It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 8, line 47, after "is" and before "wherein" Signed and sealedthis 30th day of May 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR.

ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 2M PO-105O(10-69) UscoMM-Dc wan-Poe "-5. GOVIRN'JENY PRINTING DFFICE lilio-liG-lll

2. The process of claim 1 wherein said polymerization temperature is atleast 30* C., said solubilizing conjugated diene monomer contains fromfour to 12 carbon atoms per molecule, said solubilizingmonovinyl-substituted aromatic compound contains from eight to 20 carbonatoms per molecule, said inert diluent is a paraffin, cycloparaffin,aromatic, or polar compound, wherein at least 2 gram millimoles of saidsolubilizing monomer are employed per gram millimole of said RLi, andsaid reacting is conducted for a time of from 1 to 24 hours at atemperature in the range of +30* C. to 100* C., and wherein saidpolymerization process is conducted in the presence of a hydrocarbondiluent of from four to 10 carbon atoms per molecule.
 3. The process ofclaim 2 which further includes treating the unquenched polymerizationmixture with carbon dioxide or an epoxy compound.
 4. The process ofclaim 2 wherein said polymerization process is a copolymerizationprocess, said branched polymer is a copolymer, said at least onepolymerizable monomer includes at least one conjugated diene and onemonovinyl-substituted aromatic compound.
 5. The process of claim 4wherein said polymerizable conjugated diene is 1,3-butadiene, saidpolymerizable monovinyl-substituted aromatic compound is styrene, andsaid multifunctional polymerization initiator is provided in an amountof 1 to 50 gram milliequivalents of lithium per 100 grams of saidpolymerizable monomer charged.
 6. The process according to claim 5wherein said RLi is sec-butyllithium, and said polyvinylsilane compoundis employed and is tetravinylsilane or phenyltrivinylsilane, and whereinsaid solubilizing monomer is 1,3-butadiene.
 7. The process according toclaim 5 wherein said RLi is sec-butyllithium, wherein is employed saidpolyvinylphosphine compound and is trivinylphosphine, and wherein saidsolubilizing monomer is 1,3-butadiene.